Challenges of high-fidelity virtual reactor for exascale computing and research progress of China Virtual Reactor

The virtual reactor is a sophisticated software system deployed on supercomputers to simulate physics process or predict component behaviors inside real reactors. It highly relies on advanced modeling and coupling methods, high performance computing and advanced verification and validation (V&V) techniques, which is another important method for reactor engineering design and mechanism research besides experiment. With the advent of exascale computer, it becomes mainstream trend to develop full-core high-fidelity simulation research under the help of exascale computing technology. This paper first summarizes the challenges of developing high-fidelity virtual reactor simulation in exascale computing. The challenges of high-fidelity virtual reactor simulation are introduced from four aspects: science-based modeling methods, high-resolution mesh model, scientific numerical methods , and multiphysics and multiscale coupling. Based on the architecture of exascale computer, the challenges of parallel optimization of virtual reactor for exascale computing are introduced. Furthermore, this paper introduces the recent research progress of China Virtual Reactor (CVR), which is about the parallel optimization for Chinese exascale computers and the functional extensions for achieving full-core high-fidelity simulation. The recent research progress of CVR includes multiscale simulation software of materials, fuel performance simulation software, thermal-hydraulic simulation software, full-core high-resolution meshing tool, and optimization of basic sparse operators.